BACKGROUND: We aim to determine if C-reactive protein (CRP), lipopolysaccharide-binding protein (LBP), and procalcitonin (PCT) in drain fluid can serve as screening tools for colorectal anastomotic leakage (CAL).METHODS: Patients included in this multicenter prospective observational study underwent left hemicolectomy, sigmoid resection, high anterior resection, low anterior resection, or subtotal colectomy. During the first 5 postoperative days, CRP, LBP, and PCT were determined on drain fluid. RESULTS: In total 243 patients were included, of whom 19 (8%) developed CAL. CRP levels were higher in patients with leakage on day 3 and day 5, levels of LBP were higher on days 2, 3, and 4, and PCT levels were higher on day 5. Multivariate analysis showed LBP to be significantly related to CAL. An increase in the average initial value at the first postoperative day with 1 standard deviation increased the risk of leakage by 1.6 times.This research was made possible by grant from ''Stichting Technische Wetenschappen'' (STW), Utrecht, The Netherlands. STW had no role in the study design, in collection, analysis and interpretation of the data, in writing of this manuscript or in the decision to submit.